
146 RECORDS OF THE S.A. MUSEUM 
within this genus are often slight. He uses the proportions of peduncle, rami aad 
distal spines of the uropod largely in his key; these proportions vary very little 
indeed in the same sex of Australian species of which long series of adults are 
available. The number of spaced short spines on the inner margin of the endopod 
of the uropod of the species having the pedunele of that appendage short is also 
constant; these spines may be preceded by a short seta, much more slender than 
the stouter spines, and the margin also bears minute spinules. 
In all Australian species where the adult male is available the exopodal re- 
cess in the basis of the peraeopods of this sex has a more or less developed comb- 
like outer edging: these flattened spines are absent in mystacinus Zimmer from 
New Britain (Zimmer, 1921, pp. 1384 and 139). 
Zimmer evidently does not consider necessary Paranannastacus Stebbing 
(1912, p. 164) which was established to accommodate Calman’s Nannastacis 
reptans and tardus, and it would seem that the suppression of an exopod here 
and there in the female is not of particular significance in this genus (Calman, 
1911, p. 360). The females of the Australian species, where available, have 
well-developed exopods on the first and second peraeopods; in imflatus, suhin- 
flatus and johnstoni spp. nov. there is no exopod on the third maxillipeds in 
this sex, 
As in the ease with Cumella, males greatly predominate, indeed are prac- 
tically exclusively present, in collections secured on the bottom by submarine 
light (Sheard, 1941, p. 12) and in surface material taken by tow-net. Females 
of littoral species which are found on reefs have been secured by using the 
formalin method (Hale, 1936, p. 404). 
Altogether seven species are now named as new; both sexes are available 
in four of these, the male only of the others being described. Unless, as in 
the ease of these males, the body armature is distinctive, the practice of authors 
has been to avoid naming members of the genus from this sex alone. 
Th most northerly records of the genus on Australian coasts are, on the 
west nasutus Zimmer (lat. 27° S.), and on the east suhmti Sars (lat. 16° 237 S., 
Foxon. 1932, p. 392). 
Zimmer’s keys are here modified to include all species at present named. 
KEY TO MALES OF SPECIES OF NANNASTACUS. 
The female also is known in the species marked (*). 
te 
1. Uropod with pedunele at least twice as long as telsonic somite .. i a 
Uropod with pedunele less than twice as long as telsonic somite . . =) 6 th 
2. Pseudorostrum long, the lobes meeting for a distance equal to at least one-sixth of length 
of carapace 3 
Pseudorostrum with lobes meeting for a much shorter distance ; : ‘lepturus Calman. 
3. Propodus of first peraeopod less than twice as long as dactylus longirostris Sars, 
Propodus of first peraeopod about three times as long as dactylus a4 ae of 
4. Peduncle of uropod less than twice as long as endopod ..  brachydactylus Calman. 
Pedunele of uropod at least twice as long as endopod a4 nasutus Zimmer.” 
5. Dorsum of pleon with conspicuous paired spines (or elongate tubercles) ou at least first 
five somites oe 2G ye ree ex he pa Us: 
Dorsum of pleon with conspicuous spines or tubercles on at most first two somites 73 a4 
6. First four pleon somites each with a pair of subcylindriecal dorsal processes, which with their 
apical spines are higher than vertical depth of the somites .. hansent Calman, 
Pleon somites with at most low dorsal processes, which together with their apical spines are 
never as high as vertical depth of somites ¥ an 
7, Dorsum of fourth and fifth peraeon somites strongly raised medianly e my t.% 
Dorsum of fourth and fifth peraeon somites not raised medianly be wo M 
